1. Field of the Invention
The present invention is directed to screen apparatus for a vibratory separator and, in one particular aspect to roll screen apparatus for treating drilling fluid in a shale shaker.
2. Description of Related Art
A variety of prior art vibratory separators and shale shakers have one or more screen assemblies that are removably mounted to screen holding structures or mounts in the separator or shaker. When a screen assembly is worn or damaged, the separator or shaker is turned off, the screen assembly is released from its mounting structure, and it is then removed from the separator or shaker. This is a time-consuming, labor-intensive operation which can result in significant down-time for drilling or other wellbore operations.
There has long been a need, recognized by the present inventors, for a fast and efficient way to replace screen assemblies in a vibratory separator or shale shaker. There has long been a need, recognized by the present inventors, for a way to change out a screen assembly without shutting down a wellbore operation which employs the separator or shaker.
The present invention, in certain aspects, provides a vibratory separator or a shale shaker which has a rotatable roll of screening material mounted to one end of a basket, frame or base so that the screening material can be unrolled selectively or automatically within or under a basket, screen mount, or screen container. A take-up roll mounted at an opposite end of the frame rotates to take up used screening material. Tension on the screening material is provided by one or both rolls and/or by other tensioning apparatus, e.g., but not limited to, one or more inflatable apparatuses or bladders, or hydraulic ram tensioners.
In another aspect, a roll of screening material and a take-up roll are mounted on opposing sides of a frame and screening material moves from one side to the other side of the frame as the rolls rotate. It is within the scope of this invention to have one, two, three or more such sets of rolls on a single frame. Also, such a set of rolls can be positioned on the frame to provide screening material over part of or substantially all of the entire surface area of a basket or frame or at any desired location, including, but not limited to, at a fluid-introduction area of the separator or shaker (e.g. adjacent to a xe2x80x9cpossum bellyxe2x80x9d of a shale shaker).
The screening material on a roll may be single or multi-layer and may, with multiple layers, be bonded, glued, sintered, epoxied, sewn or otherwise connected together. In certain aspects one or more glue or adhesive strips are provided along the length of the screening material to enhance sealing of a screening-material/mount-surface interface. In other aspects one, two or more beads and/or strips of glue are positioned along or near edges of rolls of screening material to provide a contact surface for a screen clamping or holding mechanism and, in certain aspects, to provide structure that inhibits or prevents the propagation of a tear or cut in the screening material.
In one particular aspect, a roll of screening material is produced by a glue machine [e.g. as described in U.S. applications Ser. No. 09/454,722, filed Dec. 4, 1999; Ser. No. 09/517,212 filed Mar. 2, 2000; Ser. No. 10/087,025 filed Oct. 19, 2002; and Ser. No. 10/037,474 filed Oct. 29, 2001; and U.S. Pat. No. 6,450,345 issued Sep. 17, 2002 co-owned with the present invention and incorporated fully herein for all purposes] In other aspects a roll produced by a glue machine is the same roll used on a separator or shaker. As needed end caps, and/or adapters may be used for mounting a roll to a shaker.
In another aspect a screen roll apparatus according to the present invention is used in conjunction with existing screen assemblies in existing separators and shakers either above them (e.g. but not limited to as a scalping screen) or below them for further screening capability.
Roll cylinders according to the present invention may be made of plastic, fiberglass, cardboard, composite, metal, steel, stainless steel, and are, in certain aspects re-fillable and reusable.
In certain aspects a visual inspection is made of a separator or shaker with screen roll apparatus according to the present invention and the rolls are rotated when such a visual inspection reveals a worn or damaged area on the screen material. In another aspect the roll apparatus is automatically indexed and rotated at regular time intervals depending on the material being treated and/or on flow rates. In another aspect sensors sense a decrease in screen throughput and/or a damaged or worn screen area and interconnected movement apparatus rotates the rolls to position new screening material in the separator or shaker.
In certain embodiments different screening material sections are wound onto a single roll in anticipation of encountering different formations or geological materials in an on-going wellbore operation and/or in anticipation of using differing fluids for such operations.
It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:
New, useful, unique, efficient, non-obvious systems and methods for providing new screening material for use within a vibratory separator or shale shaker;
Such systems and methods which provide new screening material while a vibratory separator or shale shaker continues to operate;
Such systems and methods with screening material having one or more seal strips thereon to enhance sealing of a screen/structure interface; and/or one or more edge strips thereon to inhibit or prevent tear propagation;
Such systems and methods which provide one or more sets of rolls with screening material (either with similar or different screening material) that moves either parallel to or transverse to a general direction of the flow of material in the separator or shaker;
Such systems and methods which are manually or automatically operable and which, in certain aspects, are activated by one or more sensors that sense worn or damaged screen;
Such systems and methods usable in conjunction with existing screen assemblies, separators, and shakers.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention""s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent""s object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.